This is an aluminum alloy anode (Al-Zn-In) for thrusters with 386mm (15.2") tunnels.
These are typically hydraulic models: SG420, SH550 and older SP550 HYD thrusters.
Aluminum anodes work best in salt and brackish waters. They last longer than zinc anodes and, utilizing a less toxic activator, are safer for the environment.
A securing screw is included.
This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm.
www.P65Warnings.ca.gov